Site-directed mutagenesis is used to identify amino acid residues that dictate reported differences in substrate specificity between rat hepatic neutral cytosolic cholesteryl ester hydrolase (hncCEH) and rat lung carboxylesterase (LCE), proteins differing by only 4 residues in their primary sequences. Beginning with LCE, the substitution Met(423) --> Ile(423) alone or in combination with other ...

The zebrafish (Danio rerio) is a useful vertebrate model for use in cardiovascular drug discovery. The present study aimed to construct optimized methods for the study of intravascular lipid metabolism of zebrafish. The lipophilic dye, Oil Red O, was used to stain fasting zebrafish one to eight days post-fertilization (dpf) and to stain 7-dpf zebrafish incubated in a breeding system containing ...

ACAT2, the enzyme responsible for the formation of cholesteryl esters incorporated into apolipoprotein B-containing lipoproteins by the small intestine and liver, forms predominantly cholesteryl oleate from acyl-CoA and free cholesterol. The accumulation of cholesteryl oleate in plasma lipoproteins has been found to be predictive of atherosclerosis. Accordingly, a method was developed in which ...

Diets rich in polyunsaturated fatty acids lower plasma HDL cholesterol concentrations when compared to diets rich in saturated fatty acids. We investigated the mechanistic basis for this effect in the hamster and sought to determine whether reduced plasma HDL cholesterol concentrations resulting from a high polyunsaturated fat diet are associated with a decrease in reverse cholesterol transport...

The involvement of cytosolic phospholipase A(2) (cPLA(2)) and ceramide in the accumulation of cholesteryl ester induced by the uptake of oxidized low-density lipoproteins (oxLDL) in macrophages was investigated. Uptake of oxLDL by [(3)H]oleic acid-labeled macrophages stimulated the formation of cholesteryl oleate, and this process was completely inhibited by a cPLA(2) inhibitor. Under the condi...

Steroid hormones are synthesized using cholesterol as precursor. To determine the functional importance of the low density lipoprotein (LDL) receptor and hormone-sensitive lipase (HSL) in adrenal steroidogenesis, adrenal cells were isolated from control, HSL(-/-), LDLR(-/-), and double LDLR/HSL(-/-) mice. The endocytic and selective uptake of apolipoprotein E-free human high density lipoprotein...

We have previously reported the detection of cholesteryl ester hydroperoxides, consisting mainly of cholesteryl linoleate hydroperoxides (Ch18:2-OOH), at nm levels in plasma from healthy humans (Y. Yamamoto and E. Niki, 1989. Biochem. Biophys. Res. Commun. 165: 988-993). To elucidate their production mechanism in vivo, we examined the distribution of Ch18:2-O(O)H regioisomers in blood plasma fr...

Purified acid lipase was previously shown to hydrolyze the artificial substrate, alpha-naphthyl palmitate, as well as triglycerides and cholesteryl esters and to form cholesteryl esters. To determine to what extent these activities are associated with acid lipase-containing cells in atherosclerotic plaques, we examined rabbit aortas at different stages of experimental lesion induction and human...

Steroid hormones are synthesized using cholesterol as precursor, with a substantial portion supplied by the selective uptake of lipoprotein-derived cholesteryl esters. Adrenals express a high level of neutral cholesteryl ester hydrolase activity, and recently hormone-sensitive lipase (HSL) was shown to be responsible for most adrenal neutral cholesteryl ester hydrolase activity. To determine th...

We determined cholesteryl ester transfer activity in whole plasma and in lipoprotein-depleted plasma of normolipidemic subjects and of patients with severe high-density lipoprotein (HDL) deficiency: Tangier disease, lecithin:cholesterol acyltransferase (LCAT) deficiency, and "fish-eye" disease. Transfer rates in plasma were positively correlated (r = 0.950) with rates measured in the absence of...